1. Field of the Invention
The present invention relates to a projection display apparatus and more particularly to a projection display apparatus configured to fix a reflective or transmissive liquid-crystal display (LCD) element (image-forming element) to a prism member.
2. Description of the Related Art
In conventional optical engines in projectors using light valves (e.g., LCD elements (image-forming elements)), various types of light-valve fixing units for fixing an LCD element to a fixing frame have been suggested. One such example is discussed in Japanese Patent Laid-Open No. 10-010994. As illustrated by this patent document, a light-valve frame plate 51 fixing a light valve 40R is detachably coupled with screws 56 to a fixation frame plate 54 fixed to a light incident surface 22R of light combining device 21. The projection-type display device shown in this patent document includes many intermediate members, and therefore, could be subject to a reduced shock and vibration resistance in response to dropping and to change over time, and thus exhibits reduced durability. In addition, since positioning device 57, for positioning the light valve, is disposed between temporal fixing sets, if the positioning device undergoes thermal expansion, the light valve could become distorted. Moreover, since the positioning device can be wedge-shaped, the light valve could be deformed when being inserted, depending on the strength applied. Further, since the positioning device is relatively distant from the temporal fixing device, a counter force can not be sufficient when a stress in the positioning device is released. Furthermore, since the wedge-shaped positioning device can be inserted into a small gap, the assembly operation can be difficult. Additionally, since the wedge-shaped positioning device, disposed in the small gap, is less prone to receiving light, curing the positioning device with ultraviolet light can be difficult and the direction of irradiation is limited, and therefore, the UV irradiation jig is inevitably complicated and the number of necessary irradiation operations is increased.